Tamping device



Jan. 27, 1970 B. BE'IERLE IN ETAL 3,491,562

TAMPING DEVICE Original Filed Sept. 13, 1966 INVENTORS Bernhgrd Begerleina Ulnch Belerlem ATTORNEYS 3,491,662 TAMPING DEVICE Bernhard Beierlein and Ulrich Beierlein, both of Bergische Landstrasse 309, DusseIdOrI-Gerresheim, Germany Continuation of application Ser. No. 579,125, Sept. 13,

1966. This application Dec. 6, 1968, Ser. No. 785,018 Claims priority, application Germany, Sept. 14, 1965,

Int. or. Edit 19/30 US. C]. 94-48 Claims ABSTRACT OF THE DISCLOSURE A tamping device in which a rotary vibrator is arranged on the base place of the device, there being a ballast at a level above the vibrator. This ballast is constituted at least in part by a drive motor which is arranged, for example, on a carrier plate, the same being pivotally connected to the base plate. The motor and the vibrator are poWer-transmittingly connected to each other by way of a belt-type drive which passes over a roller which is itself mounted for rotation about an axis that coincides with the pivot axis afforded by the pivotal connection between the carrier and base plates.

The present invention relates to a tamping device, that is to say, an impacting machine of the type which is used for compressing or tamping paving or other filling material and this application is a continuation of application Ser. No. 579,125 filed Sept. 13, 1966, now abandoned.

More particularly, the present invention relates to a tamping device which is equipped with a rotary vibrator that exerts a force on the base plate which is in actual contact with the material to be tamped. In conventional tamping devices of this type, the ballast weight, usually constituted by the motor which drives the vibrator, is supported resiliently on the base plate, the latter being rigidly connected with the vibrator.

In present-day tamping devices, the base plate and the ballast weight are connected to each other exclusively by way of spring elements. One drawback of such tamping devices is that the means which power-transmittingly connect the motor and the rotating vibrator to each other, i.e., the belt or chain drive, are constantly called upon to allow for the diiference in the spacing between the motor and the vibrator proper. In the case of belt-type drives, for instance, tensioning means have to be provided even if the amplitude of the vibration to which the base plate is subjected is relatively small. Even then, experience has shown that the tensioning means, such as tensioning rollers, can usually not function properly if the amplitude of vibration is over 10 mm.

It is, therefore, the primary object of the present invention to provide a tamper which overcomes the above drawbacks and, with this object in view, the present invention resides, basically, in a tamping device which incorporates a base plate and a vibrator carried thereby, as well as a ballast weight which is pivotally connected to I the base plate, there being spring means interposed between the base plate and the ballast weight.

In a preferred embodiment of the present invention, the ballast weight is made up, at least in part, of a drive motor, and there are belt means which power-transmittingly connect the motor and the vibrator, these belt means passing over rollers or the like whichthemselves are mounted for rotation about an axis that is coincident with the pivot axis afforded by the means which connect the base plate and the ballast weight to each other.

Additional objects and advantages of the present invention will become apparent upon consideration of the United States Patent 0 following description when taken in conjunction with the accompanying drawings in which:

FIGURE 1 is a diagrammatic elevational view of one embodiment of a tamping device according to the present lnventlon.

FIGURE 2 shows a modification of a detail.

Referring now the drawing and first to FIGURE 1 thereof, the same shows a tamping device incorporating a so-called ground or base plate 1 which is in actual contact with the material M to be compacted. The base plate 1 has an upwardly curved leading edge 10. Connected to the base plate 1 are an upwardly inclined frame 3 and an upwardly extending housing 4, the base plate 1, the frame 3 and the housing 4 together forming a rigid entity which rotatably supports a vibrator 2 incorporating, in the illustrated embodiment, two rotary unbalance weights 20 and 21, the same being mounted in bearings which are rigidly secured to the entity 1, 3, 4, as for example, in bearings carried by the frame 3. The unbalance weights 20, 21, are connected to each other in such a way as to rotate in opposite directions, as indicated by the arrows a and b, for example, by means of gears 20' and '21. In this way, the vibrator 2 generates directional vibrations.

The frame 3 is provided with an extension 30 whose free end is connected to one of the two components of a pivot joint 5, the other component of this pivot joint being connected to carrier plate 6. In practice, the pivot may be constituted by an axle 5a fixedly secured to the extension 30 that forms part of the rigid entity 1, 3, 4 and a sleeve 5b which is connected to the plate 6 and is turnably mounted on this axle. Consequently, the plate 6 is able to pivot with respect to the rigid entity 1, 3, 4, about a pivot axis that passes through the joint 5 and is at right angles to the plane of the drawing.

The plate 6, shown as being angled, has a free end 60 on which there is arranged a drive motor 8, such as an internal combustion engine. The motor 8 is power-transmittingly connected to the vibrator 2 by means of transmission belts 9 and belt 9 is shown as passing over a power take-off pulley 8 on the output shaft 8" of the motor 8 and over a roller 50 whose axis coincides with that of the pivot joint 5, and belt 90 is shown as passing over another roller 50, connected to the firstmentioned roller 50 for rotation therewith, and a pulley 21" connected for rotation with the unbalance weight 21.

Interposed between the rigid entity 1, 3, 4 and the plate 6 is a spring element; in the illustrated embodiment, the spring is constituted by a helical compression spring 7 interposed between the underside of the end 60 of the plate 6 and the upper side of the housing 4. The

spring thus serves to cushion the relative pivotal movement of the entity 1, 3, 4 and the plate 6 with respect to each other, this movement being shown by the double arrow 0.

Also shown is a handle 61 which is connected to the plate 6, by means of which the operator can guide the tamping device. Not shown are the conventional controls for the motor 8, such as the throttle and the clutch mechanism which may be interposed between the output shaft 8" and the power take-off pulley 8'.

It will be seen from the above that there is provided a tamping device which includes base plate means, namely, the base plate 1 and the frame 3 and housing 4 which together form a rigid entity, as well as the vibrator means 2 carried by this entity. The ballast weight means, at least a portion of which is constituted by the motor 8, are arranged at a level higher than the base plate so that the spring means which are interposed between the ballast weight means and the base plate means act against the ballast weight insofar as the pivotal movement between the ballast weight and the base plate, made possible by the pivotal connection, ie., the joint 5, is concerned.

It will also be seen that, in the illustrated embodiment, the pivot axis afforded by the joint 5 lies in the same plane as do the two axes of the counter-rotating unbalance weights 20, 21, the pivot axis being, moreover, parallel to the two axes of the unbalance weights and lying outside of the space between them, being, in fact, located at the free end of the extension 30 of the frame 3. This arrangement also causes the pivot axis to pass through a line which is at right angles to the direction of the vibrations produced by the directional vibrator 2, which line itself is intermediate the extremes of the vibrations.

One practical advantage of a tamper according to the present invention over heretofore known tampers is that the pivot axis may be used as the axis of rollers over which run the belts that power-transmittingly connect the drive motor 8 to the rotary vibrator 2. That is to say the belts, which run over rollers whose axes are coincident with the pivot axis of the joint 5, need no longer adapt themselves to different distances between the motor and the vibrator.

Moreover, the joint 5 itself is free of the tamping forces inasmuch as it lies in the same plane as the axes of the two counter-rotating unbalance weights, which means that the carrier plates, 6, 60, the motor 8 as well as the handle 61 will remain at rest.

The forward inclination of the frame 3, as shown in FIGURE 1, causes the tamper as a whole to move forwardly, i.e., leftwardly as viewed in FIGURE 1, under the influence of the directional vibrations produced by the two counter-rotating unbalance Weights 20, 21.

It will be understood that the above description of the present invention is susceptible to various modifications, changes, and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims. For example, the spring which is interposed between the base plate and the ballast weight need not be in the position shown in FIGURE 1, instead, the plate 6 and the extension 30 can be lengthened to extend beyond the joint 5, as shown in FIGURE 2 at 6 and 30', so that the spring may be interposed between the parts 6 and 30 and thus be in the region of the joint 5. In FIGURE 2, the spring is shown as being constituted by an air cushion device 40, although in practice any other suitable type of spring means may be used, as for instance, a torsion spring which is built into the joint 5.

Moreover, while the vibrator shown in the embodiment is a directional vibrator incorporating two counterrotating unbalance weights, other types of vibrators may be used, as, for instance, a pendular vibrator or a magnetic vibrator.

Instead of providing two separate belts running respectively, from the power take-off pulley 8 of the engine 8 to one of the rollers 50 and from the other roller to the vibrator pulley 21", a single belt may be run over these pulleys and rollers, in which case the rollers 50 would not be connected for rotation with each other but would be independently rotatable about the axis of the pivot joint 5.

It will, of course, be understood that the belt means which power-transmittingly connect the motor 8 to the vibrator 2 may be chain drives instead of belts, in Which case the pulleys 8' and 21" and the rollers 50 will be in the form of sprocket wheels.

What is claimed is:

1. A tamping device comprising, in combination:

(a) base plate means;

(b) vibrator means carried by said base plate means and including two unbalance weights mounted for rotation about two parallel axes, respectively, and means for con necting said two unbalance weights to each other for rotation in opposite directions thereby to produce direction vibrations;

(c) ballast weight means arranged at a level higher than said base plate means and constituted at least in part by a drive motor;

(d) means pivotally connecting said ballast Weight means and said base plate means to each other, the pivot axis afforded by said connecting means being parallel to said two parallel axes;

(e) belt means power-transmittingly connecting said motor and said vibrator, said belt means passing over roller means mounted for rotating about an axis which is coincident with the pivot axis afforded by said pivotal connecting means; and

(f) spring means interposed between said base plate means and said ballast weight means.

2. A tamping device as defined in claim 1 wherein said ballast weight means include a carrier plate which, through the intermediary of said pivotal connecting means, is connected to said base plate means, said ballast weight means further including a ballast weight supported by said carrier plate.

3. A tamping device as defined in claim 1 wherein said pivot axis passes through a line which lies in a plane which is at right angles to the direction of the vibrations produced by said vibrator means and which lies intermediate the extremes of the vibrations.

4. A tamping deviceas defined in claim 1 wherein said pivot axis, lies in generally the same plane as said two parallel axes.

5. A tamping device as defined in claim 1 wherein said pivot axis lies outside of the space between said two parallel axes.

6. A tamping device as defined in claim 1 wherein said 1 base plate means includes a base plate which is in contact with the material to be tamped, a frame which supports said vibrator means, and a housing for said vibrator means, said base plate, frame andhousing together forming a rigid entity; and wherein said ballast weight means includes a carrier plate carrying said drive motor, said carrier plate being pivotally connected to said rigid entity through the intermediary of said pivotal connecting means. i

7. A tamping .device as defined in claim 6 wherein said frame is provided with an extension at the free end of which said pivotal connecting means are located.

-8. A tamping device as defined in claim 7 wherein said spring means are interposed between said carrier plate and said housing.

9. A tamping device as defined in claim 7 wherein said spring means are located in the region of said pivotal connecting means.

10. A tamping device as defined in claim 7 wherein said frame is inclined .when the tamping device is in normal position.

References Cited UNITED STATES PATENTS 2,633,781 "4/1953 Day; 94 4s 2,687,071 8/1954 Day 94-48 FOREIGN PATENTS 500,900 3/1954 Canada. 271,578 Switzerland.

JACOB L. NACKENOFF, Primary Examiner 

